Toltrazuril + fenbendazole for cattle: Pharmacokinetics and efficacy against Eimeria spp. and gastrointestinal nematodes.

The present work evaluated the pharmacokinetics and efficacy of the association of 15cmg/kg toltrazuril +5cmg/kg fenbendazole against Eimeria spp. and gastrointestinal nematodes (GINs) in calves of different regions of Brazil (Center-West, Southeast, and South). A total of seven experiments were carried out, five of which determined formulation efficacy against Eimeria spp., considering the following aspects: therapeutic, preventive, metaphylactic, and residual efficacy. Therapeutic efficacy experiments for GINs were carried out by parasitological necropsy. The toltrazuril + fenbendazole association demonstrated ≥95% efficacy against Eimeria spp. for 21 days post-treatment (DPT). When used preventively and metaphylatically, the same association demonstrated ≥97% efficacy against E. zuernii, E. ellipsoidalis, E. cylindrica, E. bovis, E. wyomingensis and E. auburnensis. Toltrazuril + fenbendazole administered seven days before challenge was 100% effective against all these Eimeria species. Results of therapeutic, preventive, metaphylactic and residual efficacies can be related to the pharmacokinetic results, especially considering toltrazuril sulfone, which was detected in animal plasma for a longer period than the parent compound. Toltrazuril + fenbendazole achieved 100% anthelminthic efficacy against the GINs Haemonchus placei (L4), Cooperia pectinata and Oesophagostomum radiatum; 99.94% against adult H. placei; and 99.98% against C. puntacta. The association of toltrazuril + fenbendazole, associated with other measures, is an important and suitable tool for the control and treatment of Eimeria spp. and GINs in young cattle.

Flea parasitism in wild mammals in the metropolitan region of Sorocaba, São Paulo, Brazil.

Fleas are eurixenous ectoparasites that can parasitize different species of warm-blooded animals, including humans, with the possibility of causing irritation and blood spoliation. They are vectors responsible for the transmission of numerous pathogens and have a wide geographical distribution, more frequently in warm regions. Domestic animals (dogs and cats) are preferred hosts, but parasitism can also occur in wild hosts, with a greater variety of parasitic species and strong interaction between these siphonapters and their hosts. During the period from January 2021 to June 2023, flea specimens were collected from wild animals coming from the metropolitan region of Sorocaba, São Paulo. Some of these animals were animals from the zoo's own stock, which were diagnosed with parasitism during routine examinations and others were rescued from the natural environment and sent to the zoo. The flea specimens collected were packed in alcohol 700 GL and sent for microscopic diagnosis. Four groups were diagnosed at the specific level: Ctenocephalides felis, Rhopalopsyllus lutzi, R. lugrubis and Tunga penetrans, and two groups as unidentified species, belonging to the genera Rhopalopsyllus and Polygenis. The parasitized animals were all mammals, belonging to eleven different species, distributed in the Orders Carnivora, Didelphimorphia, Rodentia and Cingulata. Studies on the parasitofauna of wild animals contribute to a greater knowledge about the distribution of parasitic agents and their relationships with the host species.

As pulgas são ectoparasitos eurixenos que podem parasitar diferentes espécies de animais de sangue quente, incluindo seres humanos, com possibilidade de causar irritação e espoliação sanguínea. São vetores responsáveis pela transmissão de inúmeros patógenos e apresentam ampla distribuição geográfica, com maior frequência em regiões quentes. Os animais domésticos (cães e gatos) são hospedeiros preferenciais, mas o parasitismo pode ocorrer também em hospedeiros selvagens, com maior variedade de espécies parasitas e forte interação entre esses sifonápteros e seus hospedeiros. Durante o período de janeiro de 2021 a junho de 2023, espécimes de pulgas foram coletados de animais selvagens provenientes da região metropolitana de Sorocaba, São Paulo. Alguns destes animais eram animais do plantel do próprio zoológico, que foram diagnosticados com o parasitismo durante exames de rotina e outros foram resgatados do ambiente natural e encaminhados ao zoológico. Os espécimes de pulgas coletadas foram acondicionados em álcool 700 GL e enviados para diagnóstico microscópico. Foram diagnosticados quatro grupos a nível específico: Ctenocephalides felis, Rhopalopsyllus lutzi, R. lugrubis e Tunga penetrans, e dois grupos como espécies não identificadas, pertencentes aos gêneros Rhopalopsyllus e Polygenis. Os animais parasitados eram todos mamíferos, pertencentes a onze espécies diferentes, distribuídas nas Ordens Carnivora, Didelphimorphia, Rodentia e Cingulata. Estudos sobre a parasitofauna de animais selvagens contribuem para um maior conhecimento sobre a distribuição de agentes parasitários e suas relações com as espécies hospedeiras.

Evaluation of Larval Therapy Compared to Antibiotic Therapy in the Treatment of Skin Wounds in Rabbits.

Larval therapy (LT) is a therapeutic modality that uses larvae of necrophagous flies for the treatment of wounds. The use of this therapy presents several benefits, due to the action of the larvae that remove necrotic tissue selectively, exercising antimicrobial action, and promoting healing. There are situations in which LT proves to be the only or the best alternative for the patient, such as wounds infected by multidrug-resistant microorganisms or when treatment difficulties may lead to an indication for amputation. The purpose of this study was to compare the efficiency of LT, using larvae of Chrysomya megacephala, with that of antibiotic therapy in the treatment of cutaneous wounds infected with Pseudomonas aeruginosa. Twenty-four rabbits were used to perform the experiment, distributed in four groups: group 1, induced wound without bacterial infection; group 2, induced wound with bacterial infection; group 3, induced wound with bacterial infection and antibiotic therapy; group 4, induced wound with bacterial infection and LT. The macroscopic, microscopic, and statistical analyses indicated that LT was as effective as antibiotic therapy in wound healing.

Does bathing affect tick and flea burdens and ectoparasiticide effectiveness of a spot-on formulation (fipronil + (S)-methoprene) for dogs?

This work evaluated tick and flea burdens and the efficacy of a single topical application of 10% fipronil + 9% (S)-methoprene spot-on against experimental infestations of Rhipicephalus sanguineus sensu lato and Ctenocephalides felis felis on dogs that were submitted to regular baths for 56-days post-treatment. Four treatments (n = 24) were evaluated: no chemical treatment and no bathing (T01); no chemical treatment + bathing (T02); chemical treatment and no bathing (T03) and chemical treatment + bathing (T04). Dogs were infested with adult ticks and fleas seven days pre-treatment (-7). The ectoparasites were then counted and removed on day -5, followed by a new infestation on day -2 and treatment on day 0. Ticks and fleas were then counted without removal on day 1 and counted with removal on day 2. The dogs were then repeatedly infested with both ectoparasites on days 5, 12, 19, 26, 33, 40, 47 and 54 post-treatment. Baths and ectoparasite counts with removal were performed every 48 h before and after experimental infestation, respectively. Animals of T04 had lower (P ≤ 0.05) tick burden than animals from T01 and T02 from day 2 to day 28. For fleas, the counts varied among days of the study. Dogs from T03 presented lower (P ≤ 0.05) flea burden than dogs from T01 from day 1 until day 56. The same was true for T04 when compared to T01 from day 1 to day 42. Animals of T02 greater (P ≤ 0.05) flea burden than animals of T04 in all dates post treatment. In addition, dogs from T02 presented higher (P ≤ 0.05) flea burden than T01 from day 7 to day 28 and from day 49 to day 56. In sum, the efficacy of the spot-on formulation used declined over the time against both ectoparasites. The efficacy for ticks ranged from 0.0 to 96.5% and 0.0 to 98.52% for T03 and T04, respectively. While for fleas, the efficacy of the formulation ranged from 67.41 to 100% for T03 and 40.18 to 100% for T04. So, bathing dogs that were not treated increased C. f. felis burden but not R. sanguineus s. l. burden. The residual efficacy of the product had a shorter duration against these ectoparasites for dogs that received subsequent bathing.

Endectocide activity of a pour-on formulation containing 1.5 per cent ivermectin +0.5 per cent abamectin in cattle.

The present work aimed to evaluate, through ten different studies, the therapeutic efficacy of a new pour-on formulation, containing 1.5 per cent ivermectin +0.5 per cent abamectin, against parasites of cattle. Results obtained on trials against Rhipicephalus (Boophilus) microplus showed that the pour-on combination of 1.5 per cent ivermectin +0.5 per cent abamectin obtained superior efficacy indexes against this ectoparasite, when compared with formulations containing 0.5 per cent ivermectin, 1 per cent ivermectin and the combination of 1 per cent abamectin +20 per cent levamisole. The results of efficacy of the ivermectin+abamectin and the 0.5 per cent ivermectin against Haematobia irritans were similar. Against Cochliomyia hominivorax larvae, all pour-on formulations tested (1.5 per cent ivermectin +0.5 per cent abamectin, 0.5 per cent ivermectin and 0.5 per cent abamectin), as well as 1 per cent doramectin administered subcutaneously, were considered ineffective. Cattle medicated with 1.5 per cent ivermectin +0.5 per cent abamectin, pour-on, remained free from parasitism by Dermatobia hominis larvae during 42 days (96 per cent efficacy), while values superior to 90 per cent were obtained by 0.5 per cent ivermectin (92 per cent) and 0.5 per cent abamectin (93 per cent) until the 42nd and 35th days post treatment, respectively. Against Haemonchus placei and Oesophagostomum radiatum, the pour-on of ivermectin+abamectin showed better efficacy than the 0.5 per cent ivermectin and 0.5 per cent abamectin. As to Cooperia punctata, there was no difference regarding efficacy results obtained by the avermectins combination and abamectin. The pour-on combination of 1.5 per cent ivermectin +0.5 per cent abamectin obtained high efficacy against R. (B.) microplus, D. hominis and some species of cattle gastrointestinal helminths when compared with formulations of 0.5 per cent ivermectin and 0.5 per cent abamectin administered through the same route.

Susceptibility of Rhipicephalus (Boophilus) microplus to ivermectin (200, 500 and 630 µg/kg) in field studies in Brazil.

The present study aimed to determine the susceptibility of 17 Rhipicephalus (Boophilus) microplus populations, originating in the Southeast and Southern regions of Brazil, to different ivermectin concentrations (200, 500 and 630 µg/kg), administered through subcutaneous or topical (pour-on) routes. R. (B.) microplus populations from the states of Minas Gerais (seven populations), São Paulo (seven populations) and Paraná (three populations) were chosen for the tests. The selected cattle were allocated to treatment groups on day 0, and block formation was based on the arithmetic mean of female ticks (4.5-8.0 mm long) counted on three consecutive days (-3, -2 and -1). To evaluate the therapeutic and residual efficacies of these formulations, tick counts (females ranging from 4.5 to 8.0 mm long) were performed on days 3, 7 and 14 post-treatment, and continued on a weekly basis thereafter until the end of each experiment. The results obtained throughout this study, utilizing field efficacy studies, allowed us to conclude that the resistance of R. (B.) microplus against 200 and 500 µg/kg ivermectin is widely disseminated because all tick populations that had contact with these specific concentrations were diagnosed as resistant. However, it is possible to infer that R. (B.) microplus resistance against 630 µg/kg ivermectin was also widespread, diagnosed at six of ten analyzed properties. Resistance of these ectoparasites to 630 µg/kg ivermectin is most likely emerging in three other populations of R. (B.) microplus. Strategies of resistance management need to be quickly determined to keep the selection pressure at a minimum level in Brazil.

Evaluation of clinical safety and anthelmintic efficacy of aurixazole administed orally at 24 mg/kg in cattle.

The current study evaluated, in vivo, the clinical safety and the anthelmintic efficacy of 24% aurixazole (24 mg/kg), administered orally, in bovines. Two experiments were conducted: the first one evaluating the clinical safety of 24% aurixazole (24 mg/kg) in cattle, and a second one evaluating the anthelmintic efficacy of aurixazole (24 mg/kg) against gastrointestinal nematodes on naturally infected cattle. Based on the results of clinical safety, no alterations on clinical and haematological signs and on the biochemical values obtained in animals treated orally with aurixazole 24 mg/kg were observed. Regarding the results of reduction or efficacy, obtained by eggs per gram of faeces (EPG) counts, the formulation of aurixazole reached values superior to 99% (arithmetic means) in all post-treatment dates. In two occasions, this formulation reached maximum efficacy (100%). Comparing these results with the reduction percentages obtained by EPG counts, it is possible to verify that the values obtained by all three formulations were compatible with the efficacy results. Aurixazole reached maximum efficacy (100%) against Haemonchus placei, Cooperia spatulata and Oesophagostomum radiatum. Against Cooperia punctata, this formulation reached an efficacy index of 99.99%. Regarding aurixazole, no specific trials were conducted on the field in order to evaluate the behaviour of this molecule against helminths that are resistant to other molecules, specially isolated levamisole and disophenolat. Due to this fact, future studies will be necessary to assess the effectiveness of aurixazole against strains of nematodes that are resistant to levamisole and disophenolat, but the results of clinical safety and efficacy described in this study allow us to conclude that the aurixazole molecule, concomitantly with other measures and orally administered formulations, can be another important tool in the control of nematodes parasitizing bovines.

Sexual transmission of Toxoplasma gondii in sheep.

Male sheep of reproductive age were distributed into three groups: GI, a sheep inoculated (oral) with 2.0×10(5) oocysts of the P strain of Toxoplasma gondii; GII, a sheep infected (subcutaneous) with 1.0×10(6) tachyzoites of the RH strain of T. gondii; and GIII, a sheep kept as a control (not infected). After the inoculation of the males, 12 breeding ewes, which were not pregnant and which were serologically negative for reproductive diseases (particularly toxoplasmosis), were distributed into three groups, synchronized, and subsequently exposed to natural mating with previously inoculated males. The distribution was as follows: five ewes that underwent natural mating with the GI male, five ewes that were exposed to natural mating with the GII male, and two ewes that were mated with the non-infected male (control). Serum samples of all the ewes were collected on days -30, -14, -7, -1, and 0 (days before natural mating) and on days 1, 3, 5, 7, 11, 14, and weekly until birth; the presence of serum antibodies against T. gondii was assessed by IFAT. Using a bioassay and PCR, T. gondii was isolated from the semen of the infected reproducing sheep before mating. Following natural mating, 5 of the 12 females displayed antibodies specific for T. gondii; of these animals, two of the ewes underwent natural mating with the male inoculated with oocysts (GI) and three with the male infected with tachyzoites (GII). One of the females that displayed antibodies specific to this coccidian and that underwent natural mating with the GII sheep had a macerated fetus on the 70th day following coverage. Using a bioassay after the birth, it was possible to isolate T. gondii from samples of the "pool" of tissues from the five females that seroconverted after natural mating and from their respective lambs. Using PCR, the DNA of T. gondii was isolated from the "pool" of tissues from one and two females exposed to natural mating with the reproductive males infected with the oocysts and tachyzoites, respectively. Using this technique, it was also possible to diagnose the presence of the parasite in the "pool" of tissues from the lambs of one female that underwent natural mating with the male sheep infected with oocysts. These results demonstrated the sexual transmission of T. gondii in the sheep species with consequent vertical transmission to their lambs.

Anthelmintic efficacy of an oral formulation of Aurixazol against gastrointestinal nematodes of naturally and experimentally infected sheep.

As a result of the need to develop new active principles for the control of endoparasites in ruminants, the present in vivo study evaluated a formulation containing 24% Aurixazol (48 mg/kg), a parasiticide molecule based on disophenolate of levamisole. Two experiments were conducted: one evaluating the anthelmintic efficacy of 24% Aurixazol (48 mg/kg) against gastrointestinal nematodes in naturally infected sheep, compared to an association of ivermectin (0.2mg/kg)+albendazole (5.0mg/kg)+levamisole (7.5mg/kg) (IAL), and a second one which evaluated the persistent efficacy of the same formulation against immature stages (L4) and adults of Haemonchus contortus in experimentally infected animals. In experiment I, against H. contortus, the formulation of Aurixazol and the IAL association reached efficacies (arithmetic means) of 99.32% and 96.11%, respectively. For Trichostrongylus colubriformis, the efficacy values were 88.92% and 98.08% for Aurixazol and the IAL association, respectively. Both formulations were totally effective against Oesophagostomum columbianum (100%). The results of the statistical analysis demonstrated that the mean parasitic burden of treated animals was significantly different (P ≤ 0.05) compared to the average number of helminths diagnosed in animals from the control group for H. contortus, T. colubriformis and O. columbianum. Comparing only the treated groups, it was possible to verify that the average number of H. contortus recovered from animals treated with Aurixazol was different (P ≤ 0.05) when compared to the mean amount recovered from sheep treated with the IAL association. When evaluating the prevention of H. contortus infection in experiment II, Aurixazol did not present preventive efficacy. Up until 21 days after treatment the groups treated with Aurixazol contained less adults and L4 of H. contortus (P ≤ 0.05) when compared to the non-medicated control group. However, future studies will be necessary to assess the effectiveness of Aurixazol against nematode strains resistant to levamisole and disophenol, but the efficacy results described in this study allow to state that Aurixazol can, associated with other measures, become an important tool in the control of sheep nematodes.

Detection of Toxoplasma gondii in the reproductive system of male goats.

Male goats of mating age serologically negative for Toxoplasma gondii were divided into three groups: GI--controls (placebo) (n = 2); GII--infected with 1 x 106 tachyzoites (RH strains) (n = 2); and GIII--infected with 2 x 105 oocysts (P strains) (n = 2). Clinical, hematology, parasite and serology tests and studies of parasites in the semen through bioassay and polymerase chain reaction (PCR), and in reproductive organs (bioassay) were performed to assess toxoplasma infection. Serological titers peaked at 4096 in two animal groups infected with the protozoan. The bioassays allowed an early detection of protozoa in semen samples of tachyzoite-inoculated animals. T. gondii DNA was identified through PCR in the semen in five (Days 5, 7, 28, 49, and 70) and two (both at day 56) different days post-inoculation in GII and GIII animals, respectively. It was also possible to detect T. gondii DNA in reproductive organs (prostate pool, testicles, seminal vesicle and epididymis) of goats inoculated with either tachyzoites or oocysts. The present study suggests the possibility of venereal transmission of T. gondii among goats and it should be further assessed.

Aspects of toxoplasma infection on the reproductive system of experimentally infected rams (ovis aries).

Eight reproductive rams with no prior reproductive disease were distributed into three groups of infection with T. gondii: GI, 3 rams, 2.0 x 10(5) P strain oocysts; GII, 3 rams, 1.0 x 10(6) RH strain tachyzoites; GIII, 2 control rams. Clinical parameters were measured and serological evaluations (IIF) were performed. Presence of the parasite in the semen was investigated by PCR and bioassay techniques. The rams presented clinical alterations (hyperthermia and apathy) related to toxoplasmosis in both groups infected with Toxoplasma gondii. All the inoculated rams responded to antigenic stimulus, producing antibodies against T. gondii from postinoculation day 5 onwards. In ovine groups I and II, the greatest titers observed were 1 : 4096 and 1 : 8192, respectively. In semen samples collected from these two groups, the presence of T. gondii was detected by bioassay and PCR. This coccidian was isolated (bioassay and PCR) in tissue pools (testicles, epididymis, seminal vesicle, and prostrate) from two rams infected presenting oocysts and in one presenting tachyzoites.

Detection of Toxoplasma gondii in the reproductive system of male goats / Detecção de Toxoplasma gondii no sistema reprodutor de caprinos machos

Male goats of mating age serologically negative for Toxoplasma gondii were divided into three groups: GI - controls (placebo) (n = 2); GII - infected with 1 × 10(6) tachyzoites (RH strains) (n = 2); and GIII - infected with 2 × 10(5) oocysts (P strains) (n = 2). Clinical, hematology, parasite and serology tests and studies of parasites in the semen through bioassay and polymerase chain reaction (PCR), and in reproductive organs (bioassay) were performed to assess toxoplasma infection. Serological titers peaked at 4096 in two animal groups infected with the protozoan. The bioassays allowed an early detection of protozoa in semen samples of tachyzoite-inoculated animals. T. gondii DNA was identified through PCR in the semen in five (Days 5, 7, 28, 49, and 70) and two (both at day 56) different days post-inoculation in GII and GIII animals, respectively. It was also possible to detect T. gondii DNA in reproductive organs (prostate pool, testicles, seminal vesicle and epididymis) of goats inoculated with either tachyzoites or oocysts. The present study suggests the possibility of venereal transmission of T. gondii among goats and it should be further assessed.

Caprinos machos, em idade reprodutiva, sorologicamente negativos para Toxoplasma gondii foram distribuídos em três grupos de animais: GI (n = 2) controle (placebo), GII (n = 2) - infectado com 1 × 10(6) taquizoítos (cepa RH) e GIII (n = 2) infectado com 2 × 10(5) oocistos (cepa P). Exames clínicos, hematológicos, parasitêmicos, sorológicos, pesquisa no sêmen e em tecidos do sistema reprodutor, por meio da bioprova, e da Reação em Cadeia pela Polimerase (PCR), foram conduzidas para avaliar a infecção toxoplásmica. Os títulos sorológicos alcançaram valores máximos de 4096 nos dois grupos de animais infectados. Pela técnica da bioprova, foi possível revelar precocemente a presença do coccídio nas amostras seminais dos animais inoculados com taquizoítos. Pela PCR, foi possível identificar, no sêmen, material genético de T. gondii, em cinco (5º, 7º, 28º, 49º e 70º) e em duas (ambos ao 56º) datas experimentais pós-inoculação dos animais pertencentes aos grupos GII e GIII, respectivamente.Por esta mesma técnica, foi possível ainda isolar material genético deste protozoário, também em amostras teciduais (pool de próstata, testículo, vesícula seminal e epidídimo) dos caprinos inoculados com taquizoítos e oocistos. A presente pesquisa sugere a possibilidade da ocorrência da transmissão sexual do T. gondii na espécie caprina.

Helminth fauna of bovines from the Central-Western region, Minas Gerais State, Brazil / Fauna helmintológica de bovinos da região Centro-oeste do Estado de Minas Gerais, Brasil

Seventy-six naturally infected bovines, males and females of mixed breed, aged 8 to 12 months-old, were necropsied. The results of necropsy revealed the presence of 9 helminth genera and 16 species, with the following prevalence and mean infection intensity: Haemonchus placei (100.0 percent; 3895.5); Haemonchus similis (29.0 percent; 159.6); Cooperia punctata (100.0 percent; 5595.0); Cooperia spatulata (32.9 percent; 137.8); Cooperia pectinata (34.2 percent; 1010.5); Trichostrongylus axei (69.7 percent; 239.2); Trichostrongylus colubriformis (10.5 percent; 10.8); Trichostrongylus longyspicularis (2.6 percent; 0.5); Ostertagia ostertagi (2.6 percent; 3.1); Ostertagia lyrata (2.6 percent; 1.5); Ostertagia trifurcata (1.3 percent; 0.3); Oesophagostomum radiatum (94.7 percent; 470.9); Trichuris discolor (47.4 percent; 32.5); Strongyloides papillosus (1.3 percent; 0.1); Capillaria bovis (9.2 percent; 1.0) and Bunostomum phlebotomum (2.6 percent; 0.3). The mean parasitic load was 11,558.5 helminths per bovine. Of the 76 necropsied bovine, 92.1 percent were infected by 3 to 7 helminth species. Only 7.9 percent of hosts were parasitized by 8 different helminth species. This study includes the first report of the species Ostertagia lyrata and Ostertagia trifurcata in Minas Gerais state. It should be emphasized that while identifying the helminths collected during necropsy in the present work, observation revealed that an inversion in the mean parasitic intensity is occurring, showing diminishing numbers of Cooperia and an increase in Haemonchus compared to the values reported in the literature.

A prevalência e a intensidade de parasitismo por diferentes espécies de helmintos foram estudadas em bovinos da microrregião de Formiga, região Centro-oeste de Minas Gerais. Para tanto, foram necropsiados 76 bovinos naturalmente infectados, machos e fêmeas, SRD (sem raça definida) e de oito a 12 meses de idade. Os resultados necroscópicos revelaram a presença de nove gêneros e 16 espécies de helmintos, com a seguinte prevalência e média de intensidade de infecção: Haemonchus placei (100,0 por cento; 3895,5); Haemonchus similis (29,0 por cento; 159,6); Cooperia punctata (100,0 por cento; 5595,0); Cooperia spatulata (32,9 por cento; 137,8); Cooperia pectinata (34,2 por cento; 1010,5); Trichostrongylus axei (69,7 por cento; 239,2); Trichostrongylus colubriformis (10,5 por cento; 10,8); Trichostrongylus longyspicularis (2,6 por cento; 0,5); Ostertagia ostertagi (2,6 por cento; 3,1); Ostertagia lyrata (2,6 por cento; 1,5); Ostertagia trifurcata (1,3 por cento; 0,3); Oesophagostomum radiatum (94,7 por cento; 470,9); Trichuris discolor (47,4 por cento; 32,5); Strongyloides papillosus (1,3 por cento; 0,1); Capillaria bovis (9,2 por cento; 10) e Bunostomum phlebotomum (2,6 por cento; 0,3). A carga parasitária média foi de 11.558,5 helmintos por animal. Dos 76 bovinos necropsiados, 92,1 por cento estavam infectados por três a sete espécies de helmintos. Apenas 7,9 por cento dos hospedeiros mostravam-se parasitados por oito espécies diferentes de helmintos. Este estudo mostra o primeiro relato das espécies Ostertagia lyrata e Ostertagia trifurcata no Estado de Minas Gerais. É importante ressaltar que, no presente trabalho, por meio da identificação dos helmintos colhidos nas necropsias, foi possível observar que está ocorrendo uma inversão na intensidade parasitária média, com uma diminuição no número de Cooperia e um aumento nos valores de Haemonchus, em comparação com os valores relatados na literatura.

Histopathological analysis of the reproductive system of male dogs experimentally infected with Toxoplasma gondii / Análise histopatológica do sistema reprodutor de cães machos experimentalmente infectados com Toxoplasma gondii

The present research aimed to describe possible histopathological alterations in the reproductive system (testicles and epididymis) of male dogs experimentally infected with Toxoplasma gondii. Canines (n=10) serologically negative for T. gondii were selected and distributed into three experimental groups: GI, 3 inoculated with 2.0 x 10(5)P strain oocysts; GII, 3 infected with 1.0 x 10(6)RH strain tachyzoites; and GIII, 4 control dogs. Antibody research (IFAT) against T. gondii was realized. Toxoplasma gondii infection was confirmed by seroconversion of the 6 males infected with tachyzoites and oocysts from postinoculation day (PID) 7 and 14, respectively. At PID 70, all dogs were submitted to orchiectomy and testicle and epididymis samples were collected and histologically processed for examination under optical microscope. The following alterations were diagnosed: mild and moderate mononuclear inflammatory infiltrate in the epididymis, moderate cellular edema, hydropic degeneration and moderate interstitial fibrosis in seminiferous tubules. The histopathological results in the present research, isolation of T. gondii in testicle and epididymis fragments by immunohistochemistry and results from the literature by other authors in different tissues, all infer that the alterations observed in dogs infected with T. gondii are suggestive of toxoplasmic infection.

O presente trabalho teve como objetivo descrever eventuais alterações histopatológicas no sistema reprodutor (testículo e epidídimo) de cães machos experimentalmente infectados com Toxoplasma gondii. Para tal, 10 animais sorologicamente negativos para T. gondii foram selecionados e distribuídos em três grupos experimentais: GI - três cães inoculados com 2,0 x 10(5) oocistos da cepa P, GII - três cães infectados com 1,0 x 10(6) taquizoítos da cepa RH e GIII - quatro cães mantidos como controle. Pesquisa de anticorpos (IFI) contra T. gondii foi realizada. A infecção por T. gondii confirmou-se pela soroconversão de todos os machos infectados a partir do 7° e do 14° dia pós-inoculação (DPI) para cães que receberam taquizoítos e oocistos respectivamente. Decorridos 70DPI, realizou-se, em todos os cães, orquiectomia, e amostras (testículo e epidídimo) foram coletadas e processadas histologicamente para leitura em microscópio óptico. As seguintes alterações foram diagnosticadas: infiltrado inflamatório mononuclear leve e moderado em epidídimo, edema celular moderado, degeneração hidrópica e fibrose intersticial moderada em túbulos seminíferos. Os resultados histopatológicos do presente trabalho, aliados ao isolamento do T. gondii em fragmentos de testículo e epidídimo pela imunoistoquímica, juntamente com os resultados encontrados na literatura por outros autores em diferentes tecidos, permitem inferir que as alterações encontradas nos cães infectados com o respectivo protozoário são sugestivas de infecção toxoplásmica.